The invention relates generally to cryogenic components, and more particularly to a system and method for enhancing thermal reflectivity of a cryogenic component, for example, a magnet used in a magnetic resonance imaging system.
Magnetic resonance imaging (MRI) systems used for obtaining images of intact biological systems of a human being typically include a primary superconducting magnet provided as a superconducting coil supported by a tubular former. The primary superconducting magnet is housed in a chamber cooled to around 4 Kelvin. A vacuum vessel is used to provide thermal insulation to the superconducting magnet.
The vacuum chamber bore tube has a large internal diameter to receive a human patient and for accommodating the gradient or pulse coils used for generating field gradients in three orthogonal directions relative to the principal magnetic field. As a result of the nature of the gradient coils, it is necessary to have substantial heat insulation between the primary superconducting magnet and the gradient coils so as to insulate the primary superconducting magnet both from higher environmental temperature of the gradient coils and from the heat generated during use of these coils.
In low cryogen magnet type MRI systems, a magnet is exposed to vacuum. The surface structure of such a magnet is made of different materials, resulting in different surface finish and roughness. In addition to the magnet, components mounted on the coil former have cavities with low thermal reflectivity that results in increased heat load to the cartridge.